Offshore G-Chart® ID Codes
 How to Read Your G-chart ID Code

Garmin's G-Charts come in two sizes: Standard G-charts or Micro G-charts. Your Garmin® chartplotter will accept either the original G-chart or a Micro G-chart. They are not interchangeable. Please refer to your GPS plotter manual to determine which size is required. All part numbers listed designate standard G-charts only. If your plotter requires a micro G-chart, please add the letter "M" to the beginning of the part number listed. See below for examples. All of our Offshore G-charts are eight digits in length (nine for Micro G-charts)and use the following part number format:

Garmin Part Number Chart

Geographic Areas
AF=Africa ME=Middle East
AS=Asia NE=Northern Europe
AT=Atlantic East OC=Oceania
CA=Canada PL=Ocean Basins
CX=Central America (Mexico) SA=South America
MD=Mediterranean Sea US=United States


Assigned Number
This can be any number between 001 and 999.

Cartridge Type
S Port Services Best range is usually 1nm. Port plans to .25nm or .125nm with Port Service details
X Extra Detailed Best range is usually 1nm with port plans to .25nm or .125nm
D Detailed Best range is usually 2nm with port plans to .25nm or .125nm
F Fishing Best range is usually 2nm. Extended depth contours, bottom conditions, and fishing information. May have port plans to .25nm or .125nm
G General Best range is usually 2nm or 4nm. May have port plans to .25nm or .125nm
C Coastal Best general is usually 1nm or 2nm. No port plans. 1:100,000 to 1:40,000 scale charts


Cartridge Size
S Small ($99.00)
M Medium ($199.00)
L Large ($299.00)

Standard G-chart Examples:

GUS124XL San Juan Islands to Puget Sound (United States)
GSA012DM Colombia (South America)
GNE074DS Normandy (France)

Micro G-chart Examples:

MGUS124XL San Juan Islands to Puget Sound (United States)
MGSA012DM Colombia (South America)
MGNE074DS Normandy (France)